Apocalypse Architect: A Tower Defense LitRPG

A cosmic ray outbreak sends the environment into decline. The Zerg mutate, the land turns to desert, and resources grow scarce... Zhou Quan transmigrates into this world and draws on his years of experience beating tower-defense games to build all kinds of defensive towers against the Zerg. Soon, the major factions are contributing rare resources to build defensive towers, steel walls, and human enhancement labs... Zhou Quan is finding himself more and more fascinated by this world. But he has one big problem: obsessive-compulsive disorder!